The Canadian dollar weakened against the greenback on Thursday, and the yield on benchmark government debt slipped. The loonie was trading 0.1% lower at C$1.3508 to the greenback, or 74.03 U.S. cents, after trading in a range of 1.3457 to 1.3514. Canadian government 10-year bond yields fell 0.3 basis points to 3.482%. The yield on similar U.S. government benchmark debt fell to 4.2531%. U.S. May crude futures fell 21 cents to $81.06 a barrel on Thursday.